Efficiency of Shear Strengthening of RC Beams with Externally Bonded FRP Materials – State-of-The-Art in the Experimental Tests

2021 ◽  
pp. 113891
Author(s):  
R. Kotynia ◽  
E. Oller ◽  
A. Mari ◽  
M. Kaszubska
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Md. Ashraful Alam ◽  
Suliman A. Bakkar ◽  
Shahnawaz A. Onik ◽  
Kamal N. Mustapha

Environmental impact has become one of the major factors taken into consideration for recent civil engineering studies and projects. Thus, researchers have been concentrating on shear strengthening of existing reinforced concrete structure as an upgrade method instead of demolishing and reconstructing. In general, shear strengthening of RC beams using externally bonded steel plate has gained huge popularity. However, premature debonding of plates is the main drawback of the system, which could be mitigated using embedded connector; thus, the dimension of steel plate could be reduced significantly. Furthermore, numerical analysis on shear strengthening of beams using embedded connector would provide a great insight on the structural behavior. The aim of this research is to severely reduce the dimension of the steel plate using embedded connector for shear strengthening of RC beams and to investigate the performances of optimized shear-strengthened beams through experimental and numerical investigations. The results showed that the dimension of plate was reduced without debonding of the plate if the beam was designed for shear strengthening with the consideration of yield strength of steel plate and shear link. Experimental results showed a maximum increase in failure of 24%. The numerical results predicted accurately the structural performance of beams. The embedded connector had a great effect in deferring and minimizing the debonding failure and accordingly increasing the maximum load of shear failure between 14.5% and 24% compared to control beam.


2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Noridah Mohamad ◽  
J. Jayaprakash ◽  
Tuan Duc Ngo ◽  
...  

Strengthening of reinforced concrete (RC) continuous beams in shear have received very little attention among researchers even though most existing structures are in the form of continuous condition such as part of a floor-beam system. Therefore, in order to address the gap, a study on shear strengthening and shear repair of reinforced concrete continuous beam using Carbon Fibre Reinforced Polymer (CFRP) strips was conducted [15].  The validation of the experimental results was conducted with a simulation study using a finite element software ATENA v4 [16].  The research variables were number of layers of CFRP strips (one or two layers), wrapping schemes (four sides or three sides) and orientation of CFRP strips (0/90 or 45/135 degree’s). From the analysis of the finite element results, ATENA shows it has successfully simulated the shear behaviour of strengthened and repaired of 2-span continuous RC beams externally bonded by CFRP strips. 


2017 ◽  
Vol 11 (1) ◽  
pp. 143-152
Author(s):  
Wee Teo ◽  
Kilian Lau Meow Hing ◽  
Mohd Shahir Liew

Extensive research effort has been conducted on the shear strengthening of reinforced concrete (RC) beams with externally bonded FRP systems. However, there are still few aspects on their behaviour that are yet to be fully understood. One of them is the effect of shear interaction between internal transverse shear reinforcement and the external FRP systems. This paper is intended to study experimentally the interaction between these two shear reinforcement components. To do so, a total of five concrete beams were assembled in this investigation. All beams were properly instrumented in order to obtain as much data as possible. Four beams were externally strengthened with FRP with different strengthening and wrapping schemes. Their influence and interaction with the internal transverse stirrups in shear resistance were discussed based on the modes of failure exhibited, deflection and strain (steel and FRP) responses. Overall the results obtained are in good agreement with many researches which indicated that addition of externally bonded FRP, as a matter of fact, preserves the integrity of internal transverse stirrups. With continuous FRP sheets and U-wrapped scheme, greater FRP contribution to the shear resistance can be expected.


2013 ◽  
Vol 7 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Guibing Li ◽  
Aihui Zhang ◽  
Yugang Guo

Debonding problems of externally bonded fiber reinforced polymer (FRP) sheets in flexurally FRP-strengthened reinforced concrete (RC) beams have been a concern and a research challenge since their application of this strengthening technique. Intermediate crack induced debonding is the most common failure mode which is that the debonding initiates at the critical flexural-shear or flexural cracks and propagates towards the direction of moment decrease. To mitigate debonding failure, most Codes and proposed models take the method by limiting the allowable tensile strain in FRP laminates. This paper presents experimental tests of concrete beams flexurally strengthened with externally bonded CFRP sheets to investigate debonding initiation and tensile strain of FRP laminates. The allowable tensile strain of FRP sheets in flexurally FRP-strengthened RC beams proposed by prevalent Code provisions and models was assessed based on the data obtained from experimental programs. It has beenshown that the allowable tensile strains provided by these provisions and models have a great difference with that of experimental results and exhibit a high level of dispersion. Furthermore, the FRP laminates of most tested RC beams were debonded before reaching the proposed allowable tensile strain. The Code provisions and models are inadequate to effectively prevent intermediate crack induced debonding failure in flexurally FRP-strengthened RC members. This is known to be a critical issue in engineering design and application of RC beams flexurally strengthened by FRP sheets.


2021 ◽  
Vol 262 ◽  
pp. 113611
Author(s):  
Hasan Murat Tanarslan ◽  
Çağlar Yalçınkaya ◽  
Ninel Alver ◽  
Cihan Karademir

2012 ◽  
Vol 463-464 ◽  
pp. 249-253
Author(s):  
Jiang Feng Dong ◽  
Dong He ◽  
Shu Cheng Yuan ◽  
Qing Yuan Wang

This paper reports the results of a research work aimed at examining the use of externally bonded of fiber reinforced polymer (FRP) sheets, consisting of carbon FRP (CFRP) and glass FRP (GFRP), as a strengthening solution to upgrade the shear capacities of reinforced concrete (RC) beams. A total of 7 RC beams were constructed and tested under four-point bending, i.e. two reference beams with different concrete strength and without any FRP sheets, one beam reinforced by GFRP sheets and four beams reinforced by CFRP sheets. Externally bonded FRP shear strengthening was found very effective in upgrading the shear strength of the beams strengthened. The shear strengths of RC beams strengthened were improved greatly by FRP sheets, and the strength gain caused by the FRP sheets was in the range of 31-74%. Test results also show that the more ductile behaviour and higher ultimate strength are obtained for the beams with FRP shear strengthening by using high concrete strength.


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